Puna Geothermal Venture (PGV) is providing information regarding storm-related impacts to its 38-megawatt facility. This information is being distributed to area residents at community assistance centers including Nanawale Estates, Leilani Estates, Hawaiian Shores and Hawaiian Paradise Park Community Centers as well as Kalani Honua Retreat and J. Hara Store.

Puna Geothermal Venture

Tropical Storm-related Information from Puna Geothermal Venture

The night of Tropical Storm Iselle, Puna Geothermal Venture’s 38-megawatt power generating station on Hawaii Island was shutdown as designed. There was no “uncontrolled release” or “spill” at the facility contrary to some initial reports by commentators.

To prepare for the storm, PGV staff reviewed emergency procedures in anticipation of bad weather. PGV increased night shift crews through the storm and actively reduced the plant’s output in preparation of extreme weather conditions.

At about 7:30 p.m. Hawaii Electric Light Company (HELCO) lost both transmission lines that PGV connects to in order to transmit power to the electrical grid. With the loss of the transmission lines, the plant shutdown as designed.

By design and following approved procedures, steam was released through the emergency steam release facility. That steam was ABATED, that is, caustic soda and water were added to scrub the steam of hydrogen sulfide (H2S). This was done according to regulatory procedures, per the approved emergency response plan. This process is part of PGV’s Hawaii Department of Health (DOH) air permit requirements.

The bulk of the steam was released within the first ten minutes. The residual energy of the steam system was safely released and the wells completely shut in in approximately 45 minutes. A relief valve malfunction resulted in a low flow of steam released for slightly longer until isolated approximately 15 minutes later.

During the early part of the steam release, there was a sulfur smell. A PGV employee monitored levels at the fence line and had a peak reading of 25 parts per billion. The DOH regulation requires that we not exceed 25 parts per billion (ppb) on an hourly average. The 25 ppb reading was a “peak,” and not sustained. This emission event was well below DOH regulatory limits.

Based on the air monitoring during the shutdown, emissions remained below permitted levels and there was never any danger or violation of environmental limits. There was no need to evacuate, but Hawaii County Civil Defense alerted residents that they could evacuate voluntarily.

To put this into perspective, it is important to note that OSHA standards allow workers without protective equipment to work in an area with 10 parts per million, or 10,000 parts per billion.

Inside the Puna Geothermal Ventures plant in Puna, Hawaii

The plant has remained offline since the storm and PGV began scheduled maintenance work on Monday, August 11; this scheduled maintenance had been planned with HELCO a year ago. We anticipate restarting the plant as early as Friday, August 15 depending on transmission line availability from HELCO.

There are about 70 employees and contractors at the PGV site on Pohoiki Road in Pahoa supporting the maintenance activity, and we have no reports of illness or nausea.

PGV continues to support the local community in recovery efforts through the local Red Cross.

What it means to “shut in wells”
The pressure and flow control valves automatically shut, through computer programming overseen with human interface. This stops the flow from the geothermal resource to the generators that produce power.

2 Responses

Help please, anyone. I would love to see a schematic of this plant. The steam goes to turbines which crerate electricity and (?? something missing here like batteries to store energy to help regulate the transmission ?) and the (what?) connect to the transmission lines outward bound. These lines are strung on poles through a forest (of albizia I suppose) that when the storm went through, HelCo realized it had to turn it’s attention towards customers, otherwise it would use very heavy equipment to remove the mess and untangle it and rebuild it the same way.17 poles as I recall. The loss of the transmission line is monitored by computers and technicians and computers begin the shut down procedure to close the opening to the gases and steam, and that takes about 45 minutes. So, having no place to go, the steam is released through a filter or something that mitigates most of the harmful chemicals and metals, but the rest is released into the air. And from somewhere, stuff is pumped back into the ground to hopefully fill the rift so it doesn’t collapse.

Is that about right? Has anyone got a schematic of this particular installation. I’ve seen aerial photos and cannot figure it out, nor from the manufacturer;s diagrams. Maybe I need something between a photo and a generic diagram schematic to show me what’s where and where the energy, in it’s different forms, flows.

Puna, I don’t blame you for your worries, they are genuine. Well, worry is genuine, I mean it is based on a real possibility of some percent that something worse could happen.

Is there better technology that would eliminate some of these problems? High Energy of any kinds is dangerous, We know that just the wires on the poles could kill or burn us if we touch one. And they are all over the place. But this seems oddly disturbing to me. And, PGV is a very small installation, I gather.

NIMBY. We get the wind turbines and batteries which seem to have fallen out of favor. We’re gonna put those in the fields of UXO we have all over the place.

Cool, interesting read.
Social media definitely made this seem like it was something else.
Not that I’m going to immediately jump on the side of PGV, but this kind of response doesn’t strike me as fabricated.